LeCroy MQT300-charge to time converter

The MQT300 was developed to offer high resolution (12 bit) and wide dynamic range (18 bit) with reasonable cost, high density and fast conversion time (<10 μs). The reduced conversion time has allowed its first users the option of whether or not to develop a fast clear strategy as part of their trigger system. It can also be used, for chamber mounted applications allowing compact digital data cabling to the remote TDC. The MQT300 is a custom development produced in collaboration with the BELLE collaboration at KEK and the CLEO group at Cornell. In this collaboration Cornell and KEK were partners with LeCroy in both the specification and evaluation of the first prototypes. LeCroy (LRS division) has been responsible for the remainder of the project. The MQT300A will be available in LeCroy modules and also as a separate monolithic. The MQT300A was designed to take advantage of the latest generation of multi-hit TDCs, for example the LeCroy 1877S FASTBUS ADC. The 1877S was specifically optimized to improve conversion time and to intelligently minimize the data record size for the MQT300A application. A first prototype has been fabricated as a custom bipolar monolithic. Encouraging results are presented and have lead to design revisions that will be implemented on the next version the MQT300A. The validity of some of these revisions has been shown through both microsurgery of the existing die and extensive simulation